The NUT annual conference is underway at Gateshead

Delegates at the National Union of Teachers conference said strike threats had "clearly rattled the government".

This resulted in its offer to re-open talks on what previously had been described as "non-negotiable" issues.

The government had announced plans for the age of retirement for teachers to be raised from 60 to 65.

The union said unless those proposals were withdrawn there would be "an almighty explosion of anger".

Commitment

A member of the National Union of Teachers (NUT) executive, Tony Brockman, said the significance of the government's climbdown should not be underestimated.

Until then they had been "completely intransigent" on their proposals, including raising the retirement age, Mr Brockman said.

There was now "a clear public commitment" to genuine negotiations on all aspects of the changes.

As a result, he said, the NUT had halted its strike ballot - but teachers' expectations had been raised.

"If they went back on it there would be an almighty explosion of anger by teachers."

That would come not just from the NUT and not just from teachers but across the public sector, Mr Brockman said.

'Robbery'

Another executive member, Ian Murch, said teaching was so stressful that many teachers did not stay until they were 60.

A teacher aged 25 now would still be able to retire at 60, in 35 years' time - but with a pension and lump sum �63,000 less on average than someone retiring now.

What we want is for there to be no increase at all in the normal pension age Steve Sinnott, NUT general secretary

"That is robbery," Mr Murch said.

He added that money was there: Britain spent 9% of its wealth on pensions compared with a European average of 13%.

Stefan Sims from Enfield said the government had not backed down over the war in Iraq or student top-up fees, even though both were deeply unpopular.

But it had done so on pensions because 1.5 million people had been about to strike, with two million likely to do so towards the end of April.

The conference voted unanimously to work with other unions on defending and improving pensions.

It instructed NUT leaders to organise ballots for a series of strikes "should that prove necessary".

NUT general secretary Steve Sinnott said he did not believe that the government's offer of new negotiations was an election ploy.

"What we want is for there to be no increase at all in the normal pension age."